Life expectancy of an 86 year old woman with a heart and kidneys that only function at 30%?

My aunt is 86 years old and has a bad heart. She still lives alone and really has no other family besides me. She has to be transported to hospital via ambulance pretty frequently cause she has trouble breathing due to the fluid that builds up around her heart, but she just keeps on going. Anyone have any experience with this so I can maybe know what to expect? Thanks.